The present invention generally relates to temperature control systems for electric range surface heating elements: Yet more particularly, the invention relates to a control for an electric range surface heating element at low power or simmer settings.
As is known, electric range heating elements are commonly used on cooktop surfaces. The heating elements are most commonly controlled by infinitely variable heat control switches, also known as infinite switches. Infinite switches regulate heating element temperature by intermittently interrupting the current supplied to the heating element for a frequency proportional to the infinite switch setting.
Infinite switches are generally designed for a sufficiently high, single voltage (240 VAC, for example) to provide sufficient output for maximum heat settings. Due in part to the mechanical constraints of the infinite switches, this results in inaccurate control at low power or simmer settings. Therefore, electric range surface elements which utilize infinite switch controls can vary from 1% to 10% input during a low power simmer setting. In some cases, a low power simmer setting cannot be maintained at all. Further, tolerance studies have revealed that infinite switches do not accurately maintain a simmer setting when operating within their tolerance specifications.